Founded as the Fourth French Republic, became the modern Fifth French Republic in 1958. France withdrew from the integrated military command in 1966 to pursue an independent defense system but returned to full participation on 3 April 2009.

Iceland, the sole member that does not have its own standing army, joined on the condition that it would not be expected to establish one. However, its strategic geographic position in the Atlantic made it an invaluable member. It has a Coast Guard and has recently contributed a voluntary peacekeeping force, trained in Norway for NATO.